function externallinks() { 
if (!document.getElementsByTagName) return; 
var anchors = document.getElementsByTagName("a"); 
for (var i=0; i<anchors.length; i++) { 
   var anchor = anchors[i]; 
   if (anchor.getAttribute("href") && 
	anchor.getAttribute("rel") == "external") 
	anchor.target = "_blank"; 
    if(anchor.getAttribute("href")&&anchor.getAttribute("rel")=="top")
	anchor.target="_top";
} 

} 
window.onload = externallinks;